Process for the electric melting of metals.



c. A. KELLER-.-

PROCESS FOR THE ELECTRIC MELT ING 0F METALS.

APPLICATION ElLED 056.23, 1913.

Patent'ed July 18, 1916.

I wi bwzom V awuzutoz @111, MM

same cnARLEs ALBERT KELLER, or PARIS, ERANcE.

Specification of Letters Patent.

PRocEss FOR THE ELEcTRIc MELTrNG or METALs.

Patented July 18, 1916.

flriginal application filed August 12, 1902, Serial No. 119,385. Dividedand this application filed December 23, 1913. Serial No. 808,333.

To all whom it may concern;

I Be it known that I, CHARLES ALBERT KEL- LER, a citizen of the Republicof France, residing at Paris, France, have invented certain new anduseful Improvements in Processes for the Electric Melting of Metals, of"-which the following is a specification.

The obj ect'of the present application is an electric process formelting and refining metals and other substances, particularly iron,cast iron and steel, applicable to various metallurgical operations, forinstance, (1) the introduction into one receptacle of one or severaltappings coming from one or several melting apparatus, and theremaintaining them at a temperature produced by electric current; (2) therefining of the ma terial or its mixture with others at anymoment; (3)the melting, and the mixture of metallic waste, particularly of iron andsteel.

. The process is based on the employment of an auxiliary chamber,generally a casting ladle, the contents of which can be easilyand'rapidly interposed in an electric circuit or be subjected to theaction of the latter.

The annexeddrawing gives an example of apparatus suitable for carryingout the process, in which the figure shows the arrangement when acasting ladle is used. In said figure, the casting ladle a rests, bymeans of pivots or trunnions, on one end of a beam 6,

the other end of which carries a counterweight 0 intended for balancingthe ladle and its charge; this beam is carried by a truck d, which canbe moved on rails. This arrangement allows of bringing the ladle a tothe proximity of a melting furnace to receive the successive tappings,or to the proximity of each of a series of furnaces to receive insuccession the tappings from such furnaces; it also permits of bringingthe dle under an apparatus comprising vertical electrodes e, 6 supportedby chain tackle so as to raise or lower them into the ladle for therequirements of the operation as hereinafter described.

The ladle at, having a refractory lining, does not form part of theelectric circuit; the current enters and leaves through verticalelectrodes 6, 6, arranged above it; these electrodes can be regulatedand each constitutes in eflect a separate furnace, and in practice Iemploy more than two electrodes for each pole; this permits of alwaysbeing able to reace an electrode at Work without inter rupting ordisturbing the .course of the oper ation. If only one electrode wereprovided, its removal would cause the breakage of the circuit. On theother hand, if each pole carries a minimum of two'electrodes, it will bepossible to remove one of them and this would only result in an increaseof current in the remaining electrodes.

As an example the manufacture of iron or of steel will be described. Themetal, iron or steel contained in the ladle can be easily put into theelectric circuit through the suitable lowering of the electrodes intothe bath. The ladle is carried on a truck adapted to be moved so as tobe brought successively under the tapping orifices of furnaces of thesame battery. This arrangement will be particularly useful with abattery of electric furnaces, as the respective output of this kind ofapparatus is less than that of blastfurnaces or metallurgical meltingfurnaces of the ordinary kind. After each tapping or set of tappings themolten material finished and otherwise ready for casting contained inthe ladle is introduced into the electric circuit and the reheating iseffected by a current of suitable strength, regulatable as required. Bythese means the metal is maintained at the required temperature; the

quantity of heat necessary for this purpose will simply compensate thatquantity lost by radiation.

I The slag which will -l1ave probably been tapped with'the metal fromthe furnaces is removed in convenient quantity from the ladle so as notto be superfluously reheated.

vThis removal is eflected bysimply tilting the ladle.

The electric current is' interrupted when l the ladle has again to'beplaced under the openings of the melting furnace or furnaces, toreceive. a further tapping or tappings and-the reheating, if-requiredthentakes place as described above.

By this process a new method of working 1s reallzed; very large castingsof iron or steel can be made with apparatus, the practical output ofwhich is much less than the weight of these pieces. The temperature ofthe molten metal can be easily regulated and the metal remaining in theladle after tapplng Wlll not be wasted as often happens,

as it can be kept hot until mixed with other tappings; the founder cantherefore estimat t e amount of metal req i d forth filling up of largemolds without fear of waste resulting from too high an estimate, whichleads him sometimes to under-estimate and to spoil castingsthroughinsufficiency of metal in the ladle.

To refine or make additions .to the metal collected in the ladle itisintroduced into the electric circuit, and the removal of slag proceededwith if required, as already described; the current is then regulated soas to considerably reheat the metal to berefined, and the necessaryadditions are then made to obtain the required quality. For example,steel can be manufactured with cast iron from ordinary cupolas byrefining this castiron by the addition of oxid and, just as in theMartin furnace, one can desulfurize, dephosphorize and deoxidize.

This process therefore permits of transforming an ordinary 3 foundryinto a steel foundry. This process of refining or mixing can also beemployed for the metal coming from ordinary furnaces as well as for thatfrom electric furnaces. The process can also be easily applied to themelting and mixture of steel and iron waste which it may be required toremelt, owing to the extreme facility it olfers of taking samples,because of the continuous access it permits to the metal in the ladle.For this purpose a certain quantity of molten metalv (iron, steel orcast iron) is first introduced into the ladle, and a certain quantity oforewhich covers over the metal. The electric current is then passedintothe ladle and the operation having thus commenced, pieces of metalto be remelted and mixed are introduced into the liquid layer. Thesepieces of metal could not be placed in circuit in the empty ladle onaccount of their weak'elecmenses trical resistance, or an electriccurrent of a strength inadmissible in practice would have to be used andwhich would cause large fluctuations in the operation. With thisprocess, which utilizes the usual strengths of current employed inelectric melting, the operation is rendered normal and effective bythrowing the respective pieces of metal to be melted into the initialmetal bath formed in the ladle as described. Under I these conditions,the electric working of the apparatus is in no way disturbed and whenthe melting is complete, the additions can be made and the operationefi'ected according to the usual method of mixing and refining ofmetals. It is evident that for the refining operations in the case ofladles, neutral, acid or basic linings are employed, as the case may be.

This application is a division of my copending application Serial No.119,385, filed August 12, 1902.

I claim 1. The treatment of molten steel consisting in transferring itinto an electric fur- In testimony whereof I afii x my signature inpresence of two witnesses.

CHARLES ALBERT KELLER. Witnesses:

Hanson 0. (30x12, EDMOND JAC UAT.

